/**
 * $Id: CMP_displace.c 14767 2008-05-09 15:32:55Z blendix $
 *
 * ***** BEGIN GPL LICENSE BLOCK *****
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version. 
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software Foundation,
 * Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 *
 * The Original Code is Copyright (C) 2006 Blender Foundation.
 * All rights reserved.
 *
 * The Original Code is: all of this file.
 *
 * Contributor(s): none yet.
 *
 * ***** END GPL LICENSE BLOCK *****
 */

#include "../CMP_util.h"


/* **************** Displace  ******************** */

static bNodeSocketType cmp_node_displace_in[]= {
	{	SOCK_RGBA, 1, "Image",			0.8f, 0.8f, 0.8f, 1.0f, 0.0f, 1.0f},
	{	SOCK_VECTOR, 1, "Vector",			1.0f, 0.0f, 0.0f, 0.0f, 0.0f, 1.0f},
	{	SOCK_VALUE, 1, "X Scale",				0.0f, 0.0f, 0.0f, 0.0f, -1000.0f, 1000.0f},
	{	SOCK_VALUE, 1, "Y Scale",				0.0f, 0.0f, 0.0f, 0.0f, -1000.0f, 1000.0f},
	{	-1, 0, ""	}
};
static bNodeSocketType cmp_node_displace_out[]= {
	{	SOCK_RGBA, 0, "Image",			0.0f, 0.0f, 0.0f, 1.0f, 0.0f, 1.0f},
	{	-1, 0, ""	}
};

static float *vecbuf_get_pixel(CompBuf *vecbuf, float *veccol, int x, int y)
{
	/* the x-xrad stuff is a bit weird, but i seem to need it otherwise 
	 * my returned pixels are offset weirdly */
	return compbuf_get_pixel(vecbuf, veccol, x-vecbuf->xrad, y-vecbuf->yrad, vecbuf->xrad, vecbuf->yrad);
}

static void do_displace(CompBuf *stackbuf, CompBuf *cbuf, CompBuf *vecbuf, float *veccol, float *xscale, float *yscale)
{
	ImBuf *ibuf;
	float dx=0.0, dy=0.0;
	float dspx, dspy;
	float uv[2], col[4], colnext[4], colprev[4];
	float *vp, *vpnext, *vpprev;
	float *out= stackbuf->rect, *vec=vecbuf->rect, *in= cbuf->rect;
	int x, y, vx, vy, sx, sy;
	
	/* ibuf needed for sampling */
	ibuf= IMB_allocImBuf(cbuf->x, cbuf->y, 32, 0, 0);
	ibuf->rect_float= cbuf->rect;
	
	vec = vecbuf->rect;
	
	sx= stackbuf->x;
	sy= stackbuf->y;

	QUATCOPY(col, veccol);
	QUATCOPY(colnext, veccol);
	QUATCOPY(colprev, veccol);
	
	for(y=0; y<sy; y++) {
		for(x= 0; x< sx; x++, out+=4, in+=4, vec+=3) {
			
			vp = vecbuf_get_pixel(vecbuf, col, x, y);

			/* this happens in compbuf_get_pixel, need to make sure the following
			 * check takes them into account */
			vx= x-vecbuf->xof;
			vy= y-vecbuf->yof;
			
			/* find the new displaced co-ords, also correcting for translate offset */
			dspx = vx - (*xscale * vp[0]);
			dspy = vy - (*yscale * vp[1]);

			/* convert image space to 0.0-1.0 UV space for sampling, correcting for translate offset */
			uv[0] = dspx / (float)sx;
			uv[1] = dspy / (float)sy;
		
			if(vx>0 && vx< vecbuf->x-1 && vy>0 && vy< vecbuf->y-1)  {
				/* adaptive sampling, X and Y channel.
				 * we call vecbuf_get_pixel for every pixel since the input
				 * might be a procedural, and then we can't use offsets */
				vpprev = vecbuf_get_pixel(vecbuf, colprev, x-1, y);
				vpnext = vecbuf_get_pixel(vecbuf, colnext, x+1, y);
				dx= 0.5f*(fabs(vp[0]-vpprev[0]) + fabs(vp[0]-vpnext[0]));

				vpprev = vecbuf_get_pixel(vecbuf, colprev, x, y-1);
				vpnext = vecbuf_get_pixel(vecbuf, colnext, x, y+1);
				dy= 0.5f*(fabs(vp[1]-vpnext[1]) + fabs(vp[1]-vpprev[1]));

				vpprev = vecbuf_get_pixel(vecbuf, colprev, x-1, y-1);
				vpnext = vecbuf_get_pixel(vecbuf, colnext, x-1, y+1);
				dx+= 0.25f*(fabs(vp[0]-vpprev[0]) + fabs(vp[0]-vpnext[0]));
				dy+= 0.25f*(fabs(vp[1]-vpprev[1]) + fabs(vp[1]-vpnext[1]));

				vpprev = vecbuf_get_pixel(vecbuf, colprev, x+1, y-1);
				vpnext = vecbuf_get_pixel(vecbuf, colnext, x+1, y+1);
				dx+= 0.25f*(fabs(vp[0]-vpprev[0]) + fabs(vp[0]-vpnext[0]));
				dy+= 0.25f*(fabs(vp[1]-vpprev[1]) + fabs(vp[1]-vpnext[1]));
				
				/* scaled down to prevent blurriness */
				/* 8: magic number, provides a good level of sharpness without getting too aliased */
				dx /= 8;
				dy /= 8;
			}

			/* should use mipmap */
			if(dx > 0.006f) dx= 0.006f;
			if(dy > 0.006f) dy= 0.006f;
			if ((vp[0]> 0.0) && (dx < 0.004)) dx = 0.004;
			if ((vp[1]> 0.0) && (dy < 0.004)) dy = 0.004;
			

			ibuf_sample(ibuf, uv[0], uv[1], dx, dy, out);
		}
	}

	IMB_freeImBuf(ibuf);	
}


static void node_composit_exec_displace(void *data, bNode *node, bNodeStack **in, bNodeStack **out)
{
	if(out[0]->hasoutput==0)
		return;
	
	if(in[0]->data && in[1]->data) {
		CompBuf *cbuf= in[0]->data;
		CompBuf *vecbuf= in[1]->data;
		CompBuf *stackbuf;
		
		cbuf= typecheck_compbuf(cbuf, CB_RGBA);
		vecbuf= typecheck_compbuf(vecbuf, CB_VEC3);
		stackbuf= alloc_compbuf(cbuf->x, cbuf->y, CB_RGBA, 1); /* allocs */

		do_displace(stackbuf, cbuf, vecbuf, in[1]->vec, in[2]->vec, in[3]->vec);
		
		out[0]->data= stackbuf;
		
		
		if(cbuf!=in[0]->data)
			free_compbuf(cbuf);
		if(vecbuf!=in[1]->data)
			free_compbuf(vecbuf);
	}
}

bNodeType cmp_node_displace= {
	/* *next,*prev */	NULL, NULL,
	/* type code   */	CMP_NODE_DISPLACE,
	/* name        */	"Displace",
	/* width+range */	140, 100, 320,
	/* class+opts  */	NODE_CLASS_DISTORT, NODE_OPTIONS,
	/* input sock  */	cmp_node_displace_in,
	/* output sock */	cmp_node_displace_out,
	/* storage     */	"",
	/* execfunc    */	node_composit_exec_displace, 
	/* butfunc     */	NULL,
	/* initfunc    */	NULL,
	/* freestoragefunc    */	NULL,
	/* copystoragefunc    */	NULL,
	/* id          */	NULL
};

